A heatwave is sweeping Australia this week, bringing bushfires and other hardships, especially to farming communities. It also brings with it a puerile debate about climate change, as tends to happen whenever we experience severe weather.

Scientists have sought for decades to explain to the public what global warming is, what causes it and how it will unfold. It cannot be identified by a single event: climate change is gradual, variable and marked by increases in incidents of extreme temperature (hot and cold) as well as a rise in average temperatures over time. Indeed, the world has already become almost 1 degree hotter since pre-industrial times, an exceptionally fast shift compared with previous changes in the Earth's climate.

Yet the quality of public debate on this issue often suggests that the science, even in its simplest forms, is just too complex to be broadly understood. Hence, when a Russian ship carrying climate scientists became stuck in unexpectedly thick Antarctic ice last month, there were excited expressions of schadenfreude among those who - for whatever personal, political or commercial reasons - wish to deny the planet is warming. (''Aren't the ice caps meant to be melting? Quod erat demonstrandum …'') It is equally vapid to point to this week's heatwave as ''evidence'' of global warming.

The fact that exchanges regularly take place at this level shows just how difficult it is to build a community-wide, let alone worldwide, consensus to act to limit climate change. Almost two decades have passed since world leaders met in Kyoto to thrash out a means of preventing catastrophic global warming. Despite countless warnings and pleas about the urgency of the matter, not a lot has happened since - at least, not in Australia. The Lowy Institute regularly asks Australians if they believe climate change is a ''serious and pressing problem'' that is worth addressing even if the costs are significant. Its polling shows the number of people who agree collapsed from 68 per cent to just 40 per cent over the past seven years.

The newly elected Abbott government won office on the back of opposing even a modest penalty, or price, on carbon pollution, a policy that once had bipartisan support. Prime Minister Tony Abbott now proposes to replace the price with a vague plan of ''direct action'' that imposes no limits on polluters. Mr Abbott's chief business adviser, Maurice Newman - publicly and without any apparent embarrassment - labels climate change a ''scientific delusion'' and a ''religion''; he even says the carbon tax, which has been in place for just 1½ years, helped destroy manufacturing in this country.

Perhaps it is time to acknowledge publicly that the war is over: apathy and self-interest triumphed over the slim hope that the global community would act collectively to prevent runaway climate change. Australia's belated and extremely modest efforts - a tiny, ineffective tax and a small renewable energy target - were always insufficient, yet the government wants to dilute even those. However, as the political debate stagnated over the past decade, scientific modelling of climate change has improved and the projected outcomes for humanity have worsened. Our world, which struggled to act in the face of a likely 2-degree rise in temperatures by 2100, now faces a rise of 4 or more degrees. Such a shift will devastate global agriculture, including Australian farming. Intense storms will destroy many coastal communities, especially in the heavily populated nations to our north. The economic repercussions will transform our society.

Nonetheless, there may be some hope. Altruism - individual sacrifice for the collective good - was always unlikely on a global scale. Yet if we begin early enough to focus not so much on mitigating climate change but on adapting to it, self-interest could actually save us. Australia has decades of crucial work ahead of it: we must prepare now for the more erratic, hotter, drier weather ahead. We must rebuild our cities so they can withstand regular, ferocious storms and cope with far less fresh water. And we must ignore the hysterical antics of people like Mr Newman. Our survival is too important to pay heed to such distractions.